diff --git a/widget/src/qt/nsQApplication.cpp b/widget/src/qt/nsQApplication.cpp
index ec4324bbfee1..cc7ee0af886d 100644
--- a/widget/src/qt/nsQApplication.cpp
+++ b/widget/src/qt/nsQApplication.cpp
@@ -25,8 +25,16 @@ nsQApplication::nsQApplication(int argc, char ** argv)
     mEventQueue = nsnull;
 }
 
+nsQApplication::nsQApplication(Display * display)
+	: QApplication(display)
+{
+    mEventQueue = nsnull;
+    setGlobalMouseTracking(true);
+}
+
 nsQApplication::~nsQApplication()
 {
+    setGlobalMouseTracking(false);
     NS_IF_RELEASE(mEventQueue);
 }
 
diff --git a/widget/src/qt/nsQApplication.h b/widget/src/qt/nsQApplication.h
index 62fe1764b18c..05371a9c6976 100644
--- a/widget/src/qt/nsQApplication.h
+++ b/widget/src/qt/nsQApplication.h
@@ -27,6 +27,7 @@ class nsQApplication : public QApplication
     Q_OBJECT
 public:
 	nsQApplication(int argc, char ** argv);
+    nsQApplication(Display * display);
 	~nsQApplication();
 
 public: